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04-24-2016, 06:23 PM   #1
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Solving AF Problems - 8 Common Autofocus Problems - And Their Solutions

He uses Nikon for specific examples, however each one is sufficiently general enough to apply to Pentax.


04-24-2016, 07:30 PM   #2
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I have to watch/read this !!
I'm having such a terrible time with the K3 vs. the K5 !!!
Back soon with comments.
Thanks for sharing in the meantime.

---------- Post added 04-24-16 at 10:45 PM ----------

I just watch the video ... just as mentioned here in several threads for most of what he says but I personally think that I have to:
1. work on my technique - the K3 is not as forgiving as the K5.
2. understand that "heat refraction" can be a real PITA especially this time of the year: we still have some melting snow and shooting at long distances over humid areas will cause an "interference" of some sort .... I should know better.
3. clean the contacts ... I don't remember the last time I ever did that on any of my cameras! That could be why the AF is hunting more with the K3 vs. the K5 ??
Again, thanks for sharing !
04-24-2016, 10:04 PM   #3
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The one thing I had forgotten about was the AF detectors in the floor of the mirror box.

04-25-2016, 12:57 PM   #4
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I sold my pentax k3 and 5 lenses because the autofocus system was so poor, kept 50mm 1.4 prime for pentax mount may buy the k1 if the auto focus system is up to par or may switch brands completely. The k3 hunted so much and i would hand the camera off to somebody with group focus on and auto aperture, 7/10 shots would be slightly out of focus. The last year i had the camera i found myself using manual focus 90% of the time, which is also tough with newer lenses because the throw is so short/tight. Single point auto focus worked some of the time but Pentax is extremely far behind the competition on the subject of auto focus speed and accuracy IMHO.

04-25-2016, 02:15 PM   #5
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This video has some good ideas. I try these techniques from time to time and it never hurts to review and try again. I agree with harrisonww - Pentax needs to significantly upgrade its continuous auto focus. There are indications that the K1 auto focus is an improvement, lets hope it is a significant improvement and not just a minor tweek. Nikon has upped the anti considerably with the D500, especially considering that the 7200 is a big improvement over the Pentax K3 with respect to continuous auto focus. As harrisww I am keeping my fingers crossed that the auto focus in the K1 is much improved over the K3 otherwise I need to consider switching brands for wildlife and action photography.
04-25-2016, 02:22 PM   #6
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QuoteOriginally posted by RockvilleBob Quote
I need to consider switching brands for wildlife and action photography.
Why did you buy Pentax in the first place as AF has never been one of its strong points?
04-25-2016, 03:00 PM - 1 Like   #7
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QuoteOriginally posted by harrisonww Quote
I sold my pentax k3 and 5 lenses because the autofocus system was so poor, kept 50mm 1.4 prime for pentax mount may buy the k1 if the auto focus system is up to par or may switch brands completely. The k3 hunted so much and i would hand the camera off to somebody with group focus on and auto aperture, 7/10 shots would be slightly out of focus. The last year i had the camera i found myself using manual focus 90% of the time, which is also tough with newer lenses because the throw is so short/tight. Single point auto focus worked some of the time but Pentax is extremely far behind the competition on the subject of auto focus speed and accuracy IMHO.
Your experience is not typical. Pentax AF does not lag behind it's competition except when tracking. Straight up focus speed, there was a pop photography test a few years ago where the current Pentax, a K-5 locked focus more accurately than any other systems, and failed to find acceptable focus at half the rate Canon and Nikon cameras did. So, how good Pentax's AF is depends on how you define "good".I have a need for quick AF all day every day in poor light conditions. I've had lots of instances when I need faster AF, and they all were solved by using my F 1.7 AF adapter. All the SDM lenses are slow, it's not the camera. The 18-135, 16-85, 560mm, D FA 70-200 and D FA 150-450 all have ring motors and are quite quick. Using my 1.7 as a focus limiter on my DA*200, means the lens doesn't search as much, and it locks focus very quickly. So, just like other manufacturers, for faster focus, you need faster focusing lenses, and you're looking at the big bucks either way. But it makes you happier to switch brands, but you may struggle with your new camera as well. Although I have heard the group focus thing in a Pentax might not be as good as some. I use selectable focus points, in single point mode, and have no trouble at all. The only place I use a larger number of focus points is when shooting Birds in Flights and other tracking.

But then I understand enough about hyperlocal distances to understand where my focus point should be. So, maybe I'm a bad example for you.

There are a lot of other issues you could be facing, shooting with too wide aperture and too narrow DoF. Shake reduction really works for those slow shutter speeds but I doubt auto will select them, it's pretty conservative. There are things you can do if your images are coming out fuzzy. Or you can switch and learn a whole new system.Folks keep saying those Sony's are amazing for group shots right out of the box. Not particularly credible people, but people.

But if not understanding hyperfocal distances and DoF is your problem, it's going to be worse on an FF where at the same distance and field of view you will have even less DoF to work with.

No need to learn or understand anything with that Sony apparently. Just set it and go. Maybe that's what you're looking for. I believe they were discussing a Sony A 6300.

Last edited by normhead; 04-25-2016 at 03:08 PM.
04-25-2016, 03:12 PM   #8
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Thanks, this was helpful. I was actually coming to the board to ask a question about autofocus and kids sports and I checked some stuff the guy mentioned and seemed to have more in focus shots today. Need to try cleaning the sensors too. I also notice my issue might be the lens I was using. I'll give it go on Saturday at the next game.

04-25-2016, 03:22 PM   #9
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QuoteOriginally posted by mohb Quote
Why did you buy Pentax in the first place as AF has never been one of its strong points?
You are absolutely on the money.
I bought my first Pentax, the K-5, for interior HDR photography. I still enjoy the K-3 for that purpose and also most of my photography except for wildlife photography. I really like the Pentax with focus peaking for macro photography and landscapes.
I started wildlife photography a couple of years ago and it now represents most of my photography. Two years ago I moved to Delaware near the water and migratory birds. Living in Delaware makes getting out to shoot wildlife easy. In addition I make trips to eagle sites. I routinely traveled to PA to shoot the wild elk herd there and have a two week trip planned for shooting wildlife in the Everglades. I've added to my lenses for wildlife including the SMC 500, DA*300, Sigma 150-500 and Sigma 500 prime lens. Naturally if I started over today my camera decision would be different. So this year I'll hopefully buy a new Pentax camera with adequate continuous auto focus or buy a wildlife setup that is not Pentax and sell my Pentax telephotos and probably migrate all my photography to another camera brand over time. It would be nicer to stick with one brand of camera than have to tinker around with menu systems from two companies but I am guessing that will be less frustrating than poor auto focus performance.
04-25-2016, 04:34 PM   #10
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I had the pentax ist dl and the pentax kr before i purchased the k3.. The speed of the k3 put the other two cameras to shame however i hit focus with the ist dl at twice the rate that i did with the k3. This is a typical shot i was getting; i would have everything set for another person to simply frame the middle of the shot and click the shutter. group points, single points it didnt seem to matter the cameras keeper rate was just terrible. Having said that it didnt perform in many different scenarios, sports i can understand i used to shoot skateboarding and snowboarding and you need fast lenses and a fast tracking system I do not come to expect this from a pentax camera. I used the k3 for landscape shots and infinity focus shots and it was out of focus half of the time as well. What got me to sell the camera is the focus points would lock in for lets say a group shot of people standing still and it would be out at f4.0-5.6, fast shutter speed and decent lighting.... shooting anything faster would make the photos completely useless..There is room for the argument that I as a photographer dont utilize the k3 properly or I dont use the autofocus system properly? But i hit shots in manual focus or used the back button AF with single point to try to get a better accuracy rate. I gave this camera a lot of extra time to figure it out.. my friends canon 5d mark II autofocus points light up nice and bright with autofocus conformation and that may be a great feature in the k1. Lets just hope the points it lights up are actually in focus.

This photo was 400, f8.0. 1/80. Sigma 50mm hsm used. I had same problems with 5 lenses including the pentax 35mm 2.4

I handed the camera to my sister she took 10 shots i told her move the centre focus point around to get it to focus to the back fence and back on me so it would readjust. It hit focus 4/10 times (I would have manual focused but its hard to see in the viewfinder for anyone not used to the k3 and i wasnt taking the picture)... THE SUBJECTS ARENT MOVING! How can it possibly miss this badly. Anyways before everyone destroys me for ripping on the k3 I dont feel bad I finally separated from the k3 and I will await the k1 reviews hoping for a hands on and perhaps a happy purchase. I love the brand and the kr and the ist dl I wouldnt change for the world, best cameras I have owned.. The k3 took great photos but DAMN the focus was a major problem for me.
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04-26-2016, 05:41 AM   #11
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I'm looking at that chain link fence and it's in clear focus. This is not a Pentax problem but it might be something with your camera. In fact I'm wondering if you had the camera set up for tracking AFC, and 25 focus points selected and because of the way you had your sister focus on the fence then reposition the camera held the fence in focus instead of refocusing on you. My suggesting would be AFS, focus priority, select one focus point, get it working and then save it as U1. Then every time you hand your camera to someone set it to U1, not auto. This is part of a series of 6 or 7 and 5 were in sharp focus, your keeper rate should not be worse.

My focal length was 68mm, yours was, 50mm but mine had much smaller targets, I had not one image as bad as yours, some of mine were a little soft. Both images have extremely high contrast lighting conditions making it a little harsh and tough on the AF system, but, your fence is in sharp focus. So, something is not right with your camera. Maybe it back focuses, but this is so much I have to believe you faked yourself out with your focusing instructions and camera settings.

If changing your settings doesn't work, try checking for back focus with the lens you are using. The image is sharp, just not where you want it to be sharp.



The woman on the right in this picture, if i zoom in 1:1 I can read the label on her jacket.

Last edited by normhead; 04-26-2016 at 05:56 AM.
04-26-2016, 10:03 AM   #12
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QuoteOriginally posted by normhead Quote
Straight up focus speed, there was a pop photography test a few years ago where the current Pentax, a K-5 locked focus more accurately than any other systems, and failed to find acceptable focus at half the rate Canon and Nikon cameras did.
QuoteOriginally posted by harrisonww Quote
There is room for the argument that I as a photographer dont utilize the k3 properly or I dont use the autofocus system properly?
I had the K200D, the K-5 and K-3. One of the DA300 that I had wouldn't lock focus with the K200D and K-5 but the K-3 was able to lock focus except that the resulting images were slightly out of focus with the K-3 and perfect focus with the other two cameras. I concluded that the tolerance to lock focus was slightly relaxed on the K-3, which made sense since Pentax had a reputation to have conservative AF (more accurate than canikon but slower than canikon). And effectively, as soon as AFA or AFC is used, the K-3 is able to take photos out of focus, this fact is even written in the users manual... but AFA and AFC are dynamic focus systems for tracking, if you press the shutter fully, the camera will take pictures before AF focus locks, that's weird but that's the way it works... Now, yes, if you press the shutter fully (unless you've set the AF mode to AFS single point AND set AFS mode to focus priority), you'll get out of focus shots. The way to use K-3 AF is to half press the shutter button OR the back button AF, wait for focus confirm in the view finder (for that you have to have focus confirm light set to ON), and then start shooting and the camera will track if the subject is in motion. The only issue with that is that it is not user friendly, you need to practice on dummy targets to master the technique. Maybe canikon latest AF systems are so that the users don't have to know much about how this is working.... although I've seen reviews of users struggling to learn how to set the Canon 7DII AF modes correctly. Apparently, the 7DII also focused all over the place when the camera is let to decide on its own what to focus on. No camera can know for you what you want to focus on.

Last but not least, if you have a K-3 , use AFS single point with focus prio, you lens is calibrated and your camera takes pictures with out of focus subject, then either your camera AF has a defect and should be sent for repair, OR you moved the camera between the time of AF locked and the time the picture was taken. My K-3 is just spot on in AFS every time. On AF tracking struggles if I behave like an animal, but if I let the camera AF do its job it works. We have to distinguish between a defect K3 camera and saying that all K3 AF sucks.

Last edited by biz-engineer; 04-26-2016 at 10:10 AM.
04-26-2016, 05:42 PM   #13
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QuoteOriginally posted by harrisonww Quote
THE SUBJECTS ARENT MOVING!
The subjects - including the fence - have very low contrast because of the backlit conditions.

Shine a light on them, let the central AF sensor see enough of either a horizontal or vertical line on somebody, and don't touch the focus again - use back button or even flick to MF if you like.


04-26-2016, 09:51 PM   #14
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QuoteOriginally posted by clackers Quote
The subjects - including the fence - have very low contrast because of the backlit conditions. Shine a light on them, let the central AF sensor see enough of either a horizontal or vertical line on somebody, and don't touch the focus again - use back button or even flick to MF if you like.
Clackers, you have a K30 or K-S1, so that may be your perception. The K-3 (what's being mentioned above) has an AF sensitivity down to -3ev. normally it is able can lock focus in almost dark.
I have a K-3, given the photo posted above, I would really need to force my K-3 to miss focus on this shot, either by "accidentally" selecting the wrong AF point, or by setting AF to "shot priority" (as opposed to "focus priority") AND fully pressing the shutter without any wait for AF. With a shot live posted above and AFS focus prio, there is no way the K-3 will take the shot.

I've shot 25K images with the K-3, and I did not have a single AFS shot miss focused (I've had issues with AFC but AFC isn't for static shots). So, either the K-3 used here has a defect, or I have a "good copy" of the K-3, or some of the information was omitted in the post. You can't consider that the K-3 behaves the same as a K30 or K-S1.

Last edited by biz-engineer; 04-26-2016 at 09:57 PM.
04-26-2016, 11:05 PM   #15
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QuoteOriginally posted by biz-engineer Quote
So, either the K-3 used here has a defect, or I have a "good copy" of the K-3, or some of the information was omitted in the post. You can't consider that the K-3 behaves the same as a K30 or K-S1.
Yes, I agree with all of your first sentence, BE, and most of your second.

The low light behaviour will be similar except that the K-3 is rated to -3eV, my bodies to -1eV.

Low contrast behaviour is another thing - have you seen a focus chart like those used to determine those ratings?

That's made up of black and white shapes containing very distinct edges. The people's faces in the picture above don't look like that.

At least your K-3 has nearly all its AF points able to use vertical lines as well as horizontal.

My K-30 only has nine of those cross points. Luckily, I'm a focus and recompose guy, so I only want a single AF point, in the centre, and I'm happy.

Last edited by clackers; 04-26-2016 at 11:11 PM.
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